Physical Access Control systems have historically included access control “readers” mounted at or near the entrance doors of commercial facilities. When a user nears the door, they present a badge to the reader typically mounted near the door. Legacy access control readers and credentials have historically worked using the principle of mutual inductive coupling between the DC powered reader and a credential without an internal power source. In other words, the reader produces an AC magnetic field at the carrier frequency that is present in the “proximity” of the reader antenna. When the credential is brought into the field such that it is inductively coupled to the reader, the credential harvests power from the field and uses that power to run the electronics in the credential. The credential may be in the form of a card, identification badge, or fob. This allows users to enter an area without the need for a physical key. Additionally, access privileges for a user can be added or revoked by an administrator, without impacting other users. Thus, physical access control systems are an important aspect of security for businesses, residences, airports, hospitals, and many other venues. Therefore, it is desirable to have improvements in physical access control systems.